I'd like to dig into this a little further for you. Have you ever used Google Play Music before with your gmail account and cashed in on one of their previous free trials?

Per usual, the trial is only available to new Google Play Music subscribers, not those who may have paid for the service in the past and let their subscription lapse.

Just trying to clarify so I can help figure this out with you. I also notice on my Pixel when I open Google Play Music it says "Samsung customers: Get your first 30 days on us, then just $9.99 per month." Super interesting stuff! We need our Samsung folks to chime in!

With the purchase of a Galaxy S8, Galaxy S8+ or Galaxy Tab S3 device, users will also receive a free three-month subscription to Google Play Music, and thus ad-free, on-demand access to over 40 million songs, as well as tailored playlists that cater to any mood or occasion. In addition, with access to YouTube Red (where available), users can enjoy ad-free videos during the trial period.

There are no "*" that it's only for new customers. I can't say however that I've had any luck activating the promotion for me. I called Google, who told me to call Samsung. Did that, and after 2 hours on hold, was told I had to call Google.

This is the screen that I also received but I might have received the 90 day offer because I have never subscribed to any previous 30 day trial with google music. Do you have more than one gmail account on your phone? The 90 day trial might work with one of your other accounts?